BEIJING, Feb 27 (Reuters) - Chinese President Xi Jinping is to take the reins of a government body for Internet security and aims to turn China into a "cyber power", official state media reported on Thursday, as the country steadily tightens its grip online.

Since coming to power, Xi has presided over an intensifying online crackdown that has drawn criticism from rights groups and dissidents at home and abroad.

China has also faced growing accusations of carrying out state-sponsored hacking attacks around the world, charges the government strongly denies.

Among the security body's aims would be to coordinate Internet security among different sectors, and to draft national strategies, development plans and major policies, Xi was quoted as saying by Xinhua.

"Efforts should be made to build our country into a cyber power," he said, adding that without Internet security, there was no national security.

Last year a secretive Chinese military unit believed to be behind a series of hacking attacks was brought to light by a U.S. security group, and in December another security firm said Chinese hackers had spied on European foreign ministries before a G20 meeting.

Xi also said that working on public opinion online was a long-term responsibility, and the Internet could be used to "spread discipline".

Laws would be drawn up to "perfect Internet information content management", to help manage cyberspace and protect people's legal rights, he said.

Last year, China's Communist Party renewed a heavy-handed campaign to control online interaction, threatening legal action against people whose perceived rumours on microblogs such as Sina Weibo are reposted more than 500 times or seen by more than 5,000 people.

Rights groups and dissidents have criticised the crackdown as another tool for the party to limit criticism and to further control freedom of expression.

The government says such steps are needed for social stability and says every country in the world seeks to regulate the Internet.

China has the world's most sophisticated online censorship system, known outside the country as the Great Firewall. It blocks many social media websites, such as Twitter, Facebook, YouTube and others, along with many sites hosted in Taiwan and those of rights groups and some foreign media agencies. (Reporting by Paul Carsten; Editing by Raissa Kasolowsky)